WASHINGTON — Republican congressional nominee Howard P. (Buck) McKeon has returned two campaign contributions totaling $350 to a gay Republican advocacy group because he says he does "not support the fundamental positions" the group espouses.

"I think that, politically in this district, taking money from gays is just not a smart thing to do," said McKeon, a candidate in the newly drawn 25th district, which encompasses the Antelope and Santa Clarita valleys and parts of the northern San Fernando Valley.

His action, disclosed in an interview this week, drew a heated rejoinder from one of the former Santa Clarita mayor's November opponents, who claims McKeon has engaged in a "crass, insincere form of political manipulation."

McKeon, a conservative, told The Times in late July that he was unaware of the Log Cabin Federation's Political Action Committee, even though the group had given him checks for $250 and $100 during his tough primary race in the northern Los Angeles County district.

He said at the time that, while he believes "all people should be able to live the lifestyle they want to live," he opposed two of the Log Cabin Federation's priorities: passage of an anti-discrimination bill and a change in Pentagon policy to permit openly homosexual men and women to serve in the military.

Two weeks after a story about the contributions appeared in The Times, McKeon returned the money to the Log Cabin PAC.

In an Aug. 13 letter to Republican political consultant Ron Smith--who had given $100 to the Log Cabin PAC but earmarked it to be forwarded to McKeon's campaign--the GOP candidate said he was doing so "because I do not support the fundamental positions the Republican Log Cabin PAC advocates." He cited an anti-discrimination measure and the military service issue.

The 25th district is heavily Republican and conservative.

Smith, whose firm is based in Los Angeles, could not be reached Wednesday. But Jim Baird, the Log Cabin PAC treasurer, said he was disappointed by McKeon's decision. "I'm sorry that certain Republicans feel that way," Baird added.

He contrasted McKeon's posture with that of GOP Assembly candidate Christine Reed of Santa Monica, who said she was proud to have Log Cabin support when her $250 contribution was challenged by primary opponents. The PAC gave her another $450; she won the nomination.

James H. (Gil) Gilmartin, McKeon's Democratic opponent and a Santa Clarita attorney, could not be reached for comment.

But Rick Pamplin, a Palmdale businessman and educator who is running as an independent, challenged McKeon's assertion that he did not know the identity of the Log Cabin group, which has become increasingly active in Republican politics in recent years.

"It was the most crass, insincere form of political manipulation I've ever seen," Pamplin said. Homosexual Republicans who regarded McKeon as an ally may have made the difference in his 705-vote primary victory over Assemblyman Phillip D. Wyman and four others, he added.

"Once he won the primary, he changed his position," said Pamplin, who supports both an anti-discrimination bill and allowing homosexuals to serve in the military. "He returned their money; he stabbed them in the back."

Pamplin said he based his charge on conversations with Tammy Thomas, who managed McKeon's office in the primary but is now Pamplin's deputy campaign director. Thomas said in an interview that she told McKeon that the Log Cabin members represented gay activists when the group first called him in late March.

"I explained it to Buck and said, 'You probably don't want to call them back,' " Thomas said. "I did tell him who Log Cabin was."

She said the checks came in shortly before the June 2 primary and were sent to the campaign treasurer's office. Copies were forwarded to the campaign headquarters, she added.

McKeon was traveling Wednesday and could not be reached. But his campaign manager reiterated that the candidate was unaware of Log Cabin's identity until The Times informed him of it in late July.

"They sent us the checks specifically because they didn't like Phil Wyman," Armando Azarloza said of the PAC. "It was more of an anti-Wyman donation."

Pamplin, he said, "doesn't have any issues to run on and so he wants to throw mud at us. This is pure mud. It's not an important issue."